The complaints of insomnia and excessive daytime sleepiness are covered later in this section. The circadian rhythm disorders are separately identified since they form a physiological entity. The links between the pathophysiology, clinical features and treatment of these sleep disorders are emphasized throughout these chapters.

This approach has many similarities to, but also some differences from, the widely used 1997 third revision of the International Classification of Sleep Disorders (ICSD) produced by the American Sleep Disorders Association (ASDA) in association with other national and international sleep societies.

Sleep disorders are frequent processes, both as a symptom associated with other diseases and as independent disorders. However, only in the last 4 decades has Sleep medicine gained its position among the medical specialties.

In fact, it was only in these years that significant advances were obtained in the study of the etiology and treatment of these disorders. Similarly, the different classifications have been evolving over the years.

First, they were based upon the clinical symptom; later on, more emphasis was given to the diseases. Finally, in 2005, the new classification was once again based on the symptoms. More than 90 disorders are listed in this latest classification, and an attempt is made to include the symptoms and the diseases of sleep, as well as those in which sleep disorders are fundamental.

It is essential to have a clear idea of this complete classification of sleep disorders in order to deal with these patients appropriately.

The International Classification of Sleep Disorders (ICSD) was produced primarily for diagnostic and epidemiologic purposes so that disorders could be indexed and morbidity and mortality information could be recorded and retrieved.

This classification is not intended to provide a differential diagnostic listing of sleep and arousal disorders. A differential diagnostic listing is presented on page 331 and is included to assist the clinician in diagnosing disease related to one of three major sleep symptoms: insomnia, excessive sleepiness, or an abnormal event during sleep.

The ICSD is consistent in style with International Classification of Diseases (ICD-9-CM) classifications for disorders affecting systems such as the cardiovascular or respiratory.

The ICSD consists of four categories. The first category comprises the dyssomnias (i.e.,the disorders of initiating and maintaining sleep and the disorders of excessive sleepiness).

Rapid eye movement sleep, or REM, is one of the five stages of sleep that most people experience nightly....

Childhood Sleep Disorders

Newborns spend 50% of their sleep time in rapid eye movement (REM) sleep...

Sleep and Sleep Disorders

The prevalence of sleep complaints increases dramatically with age...

Common Sleep Disorders

A number of sleep disorders can disrupt your sleep quality and leave you...

Your Guide to Healthy Sleep Introduction

Think of everything you do during your day...

Sleep and gender

There are only minor differences in sleep requirements between males and females...

Classification of sleep disorders

Sleep disorders are frequent processes, both as a symptom associated with...

Timing of sleep

A regular time of going to bed, going to sleep, waking up...

Structure of sleep (sleep architecture)

External influences and some internal stimuli have less influence on the brain...

There are currently three systems used to classify sleep disorders:

ICSD-3 is published in association with the European Sleep Research Society, the Japanese Society of Sleep Research, and the Latin American Sleep Society. It distinguishes six subcategories of sleep disorders:

The Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition

(commonly known as the DSM-V), published by the American Psychiatric Association, Washington, DC, 2013.;

This system lists 10 "sleep-wake disorders," conditions (or groups of conditions) that are manifested by disturbed sleep that cause both distressed and impaired functioning during the daytime:

Insomnia disorder

Hypersomnolence disorder

Narcolepsy

Breathing-related sleep disorders, including:

Obstructive sleep apnea hypopnea

Central sleep apnea

Sleep-related hypoventilation

Circadian rhythm sleep disorders, including:

Advanced sleep phase syndrome

Irregular sleep-wake type

Non-24-hour sleep-wake type

Non-REM (NREM) sleep arousal disorders

Nightmare disorder

REM sleep behavior disorder

Restless legs syndrome

Substance- or medication-induced sleep disorder.

The International Classification of Sleep Disorders, Third Edition (ICSD-3), published by the American Academy of Sleep Medicine, Chicago, 2014.

ICSD-3 is published in association with the European Sleep Research Society, the Japanese Society of Sleep Research, and the Latin American Sleep Society. It distinguishes six subcategories of sleep disorders:

Insomnia

Sleep Related Breathing Disorders

Central Disorders of Hypersomnolence

Circadian Rhythm Sleep-Wake Disorders

Parasomnias

Sleep-Related Movement Disorders

The International Classification of Diseases, 10th edition (ICD-10), published by the World Health Organization, Geneva, Switzerland, 1994.

The ICD-10 system sets aside two areas for sleep disorders: organic (ICD-10 code: G47) and nonorganic (ICD-10 code: F51), but it only includes a few actual sleep disorder diagnoses.

The United States still uses a precursor to the ICD-10, the ICD-9-CM (CM stands for "clinical modifications") - although the country will change over to the ICD-10 system in October 2015. ICD-9 recently incorporated most sleep disorder diagnoses listed in ICSD-2.

The second category, the parasomnias, comprises the disorders of arousal, partial arousal, or sleep stage transition, which do not cause a primary complaint of insomnia or excessive sleepiness. The third category, sleep disorders associated with mental, neurologic, or other medical disorders, comprises disorders with a prominent sleep complaint that is felt to be secondary to another condition. The fourth category, proposed sleep disorders, includes those disorders for which there is insufficient information available to confirm their acceptance as definitive sleep disorders.

Textual content is included for all the ICSD disorders that are listed in Axis A.

THE AXIAL SYSTEM

The International Classification of Sleep Disorders (ICSD) uses a multiaxial system for stating and coding diagnoses both in clinical reports or for data base purposes. The axial system uses International Classification of Diseases (ICD-9-CM) coding wherever possible. Additional codes are included for procedures and physical signs of particular interest to sleep disorders clinicians and researchers.

Modifying information,such as severity, duration, and symptoms, also can be specified and coded by a special ICSD sleep code. Diagnoses and procedures are listed and coded on three main "axes."

Other Sleep Disorders

Other Physiological (Organic) Sleep Disorder

Other Sleep Disorder Not Due to Substance or Known

Physiological Condition

Environmental Sleep Disorder

Disorders Association (ASDA) in association with other national and international sleep societies [25] (Table 1.6). This groups insomnia and excessive daytime sleepiness as dyssomnias and distinguishes them from disorders occurring during sleep (parasomnias).

It also has two other categories which are less satisfactory. First, a group of medical and psychiatric disorders which includes epilepsy and mood disorders, all of which interact with the sleep mechanisms in a similar fashion to the disorders in the dyssomnia and parasomnia categories. The second group of 'proposed sleep disorders' is heterogeneous and emphasizes the descriptive aspects and includes partly developed concepts such as the 'sleep choking syndrome'.

The 2005 version recognises eight categories of sleep disorder [26] (Table 1.7) with insomnia and hypersomnias separated, but motor disorders during sleep included in the parasomnia, sleep related movement disorders and isolated symptoms sections. The term 'parasomnia' has not been used in this book because of the wide range and heterogeneous nature of sleep conditions that it has come to represent, but the important influence of drugs is recognised by a separate chapter devoted to their effects. The AASM 2005 classification includes drug related sleep disorders in several different categories, but excludes disorders such as sleep related epilepsy and several medical and psychiatric disorders causing sleep related symptoms.

It's easy to make a financial decision based on what you need right now, but making an informed choice will benefit you in the long run. Meet a former Red Sox pitcher who picked security over an uncertain future